The present invention relates to improvements in a cutting tool of the plier type which is commonly used to cut various materials of differing shape and hardness.
Cutting tools of the plier type similar to the present invention are now in widespread use. Cutting pliers utilizing diagonal and straight jaws are used to cut multiple shapes of various materials. However, when they need to cut a geometric shape such as a ring encircling tubing, the cut needs to be done with the extreme edge of the jaws.
This explains why plumbers and other persons have been using hacksaws for over twenty years to cut off compression rings of medium strength materials such as copper or aluminum. Indeed, many plumbers will cut the flexible pipe and throw away the fittings to avoid the difficulties of cutting a ring with currently available tools.
Other proposed systems to cut these rings have included the use of a roto-tool with a cutting wheel. A tool bit closing tool has also been developed for cutting such rings. These two systems to cut the rings from a water pipe or conduit are more complicated, more costly, and do not provide the capability to extract the ring after it is cut. Also, the devices do not necessarily provide multiple size cutting capability.
It is an object of the present invention is to provide a simple, reliable, and versatile hand tool which permits plumbers and other users to cut a copper or similar ring surrounding a conduit when such action is needed. Examples of the use of such rings include their use on current water lines, cutting off plugs after pressure testing, or dismantling a fitting.
A second object of the present invention is to provide a ring cutting tool in which the jaws and cutting edge geometry permit an easy lateral cutting and breaking apart of a compression ring in a first motion, and its pulling away from the pipe in a second motion.
A third object of the present invention is to permit the operator of the tool to pull off the cut ring through a second operation simply by using the ring cutting tool to xe2x80x9cbitexe2x80x9d the ring near the cut area and pull on the tool to unroll and free up the ring.
A fourth object of the present invention is to provide a ring cutting tool which can be used with any size of ring since the cut is done laterally from edge to edge. A still further object of this invention is to combine the previous noted advantages of the ring cutting tool which incorporates other functions such as a hammer, wire cutters, pliers, etc.
A still further object of the present invention is to provide a ring cutting tool which can be manufactured in a similar manner as current plier tools.
According to one aspect of the present invention, there is provided a ring cutting tool suitable for cutting a ring from tubing, the ring cutting tool comprising a first member having a first member jaw at one end thereof and a first member handle at an opposed end thereof, a second member having a second member jaw at one end thereof and a second member handle at an opposed end thereof, the first jaw having a first jaw cutting surface formed thereon, the second jaw having a second jaw cutting surface formed thereon, the first and second members being pivotably connected together such that the first jaw cutting surface and the second jaw cutting surge can move from a first spaced apart position to a second position wherein the jaw cutting surfaces are in a substantially abutting relationship and the first jaw cutting surface and the second jaw cutting surface defining an angle of between 20xc2x0 and 35xc2x0 when in the second position.
The cutting tool of the present invention may have the same general characteristics of current cutter pliers providing a mechanical advantage of 5 to 7, where 40 to 50 lbs. of handle pressure provide 200 to 350 lbs. of force at the tip of the jaws, which is sufficient to cut through any copper ring used currently in flexible water line. Those copper rings with a thickness of 0.050 inch to 0.060 inch and a width of {fraction (5/16)} inch to xe2x85x9c inch may easily be cut by the tool of the present invention with a single closure of the jaw across the ring.
As aforementioned, the ring cutting tool of the present invention is suitable for cutting rings surrounding a conduit. In order to achieve the above, the blades have a geometry which permits the blades to bite into the ring and not slip therefrom.
It is preferred that the jaw cutting surfaces, in the preferred embodiment, and when in a closed relationship, define an angle of between 20xc2x0 and 35xc2x0. Even more preferably, the angle is between 25xc2x0 and 30xc2x0. It is also preferred that the edges of the jaw adjacent the conduit slope backward therefrom to provide sufficient clearance. The angle of slope is preferably between 5xc2x0 and 25xc2x0 and even more preferably, between 8xc2x0 and 15xc2x0.
The ring cutting tool of the present invention may incorporate many conventional abilities therein. Thus, the two jaws may have the capability of functioning as a hammer and/or claw. Even further, there may be provided the capability, as will be discussed in the preferred embodiments, of the tool functioning as a wire cutter, a conventional plier, etc.